For saving the network building cost of operators and utilizing the network resources more effectively, while providing the subscribers with the services with low charge rate and high quality, a one-stop wireless access solution is provided, and a wireless access equipment which is called home base station is introduced; the home base station can provide various wireless access functions. When a subscriber uses the home base station in places, such as home, market, company and school, the operators can provide a preferential tariff; besides, a load of a common cell which is called a macro cell can be reduced; the one-stop wireless access solution is a very good optimized solution for indoor coverage.
At present, the home base station has three access modes: a closed mode, an open mode and a hybrid mode. Wherein a home base station of the closed mode only allows authorized subscribers to access and provides services for them; a cell which is covered by the home base station of the closed mode is called a CSG cell. A home base station of the open mode allows all subscribers to access and provides services for them; a cell which is covered by the home base station of the open mode is called an Open cell, which is similar to a macro cell. A home base station of the hybrid mode allows authorized subscribers to access and provides services for them as well as allows unauthorized subscribers to access and provides services for them; a cell which is covered by the home base station of the hybrid mode is called a Hybrid cell. Aiming at the authorized subscribers and the unauthorized subscribers, the Hybrid cell plays different roles: for the authorized subscribers, the Hybrid cell is regarded as a CSG cell; and for the unauthorized subscribers, the Hybrid cell is regarded as an Open cell.
Because the CSG cell or the Hybrid cell has advantages on tariff and can reduce the load of the macro cell, a CSG User Equipment (UE) will access a network to the best of its ability through an authorized CSG cell or Hybrid cell. When the UE wants to access the CSG cell or Hybrid cell, first of all, it needs to measure the CSG cell or Hybrid cell and other adjacent cells, and report the measured signal quality of these adjacent cells to a network side, and then the network side determines whether to access the CSG cell or Hybrid cell.
Under a connection status, the process of the cell measurement mainly comprises: the network side sends a measurement control message to the UE, wherein the measurement control message contains a measurement identity, measurement object, a report configuration and other attributes related to the measurement. The UE performs the measurement according to the measurement object and the report configuration in the measurement control message, and generates a measurement report according to the measurement result and reports the measurement report to the network side.
The UE learns carrier frequency of an adjacent cell through the attributes of the measurement object in the measurement control message, or through historical information stored by the UE itself; the UE completes the synchronization in time with the adjacent cell by searching for Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) of the adjacent cell, at the same time, can acquire the Physical Cell Identity (PCI) of the adjacent cell; at the moment the UE can read a Reference Signal (RS) of the adjacent cell, so as to acquire the signal quality of the adjacent cell. The current network operators, when performing network planning, reserve part of physical resources, such as PCI, to be dedicated to CSG cells, and notify the UE of configuration of the reversed physical resources in a manner of broadcasting or signaling, etc. so that the UE can determine whether the cell is a CSG cell by scanning a physical layer. Usually, the UE stores the location information of the area which the UE can access, and the area is called fingerprint area or footprint area, at the same time, the UE may store the information, such as carrier frequency, PCI, CGI and other information of the CSG cell which the UE can access, and the information is called historical information.
In the current protocol, the precondition that the UE initiates measurement of an intra-frequency, an inter-frequency and a heterogeneous system configured by the network side is: s-Measure is not configured, or Reference Signal Received Power (RSRP) of a serving cell, which is filtered by a layer 3, is lower than the s-Measure while the s-Measure is configured. Wherein the s-Measure is an designated RSRP value. For describing conveniently, the disclosure calls “a RSRP value of a serving cell which is filtered by a layer 3” as servingRSRP for short.
Configuring the s-Measure aims to reduce the frequency of measurement and report, that is to say, when there is s-Measure configured, and the servingRSRP is always higher than the s-Measure, the UE does not initiate a measurement task configured by the network side. In this case, if there is a CSG cell or a Hybrid cell which is allowed to access near the UE, it is possible that the UE cannot measure the CSG cell or Hybrid cell to realize a handover; therefore, the CSG cell or Hybrid cell cannot play the role well and the load of the macro cell is increased, as a result, the interests of subscribers cannot be protected well.